MotherOfChickens
MotherDucker
There are loads available but one that has some data behind it and one I rate is Orego-Stim. Mine get it going through moult and any other time I feel they might need it-unseasonably bad weather for example (Scotland!) and I also increase their protein by feeding peas from moult through the winter (Mashams flaked but any peas will do) .
Respite Poultry and Game tonic is also useful (although since using the above I've not bothered with it) but has a short shelf life.
And don't undervalue worming, even if your hens free range and you see no signs of worms its worth doing-Marriages does pellets with flubenvet (the only licensed poultry wormer in the UK and the only one to do all worms) already mixed in. Keep the hens space limited for 7 days and feed the pellets-mine are done 2 or three times a year.
Respite Poultry and Game tonic is also useful (although since using the above I've not bothered with it) but has a short shelf life.
And don't undervalue worming, even if your hens free range and you see no signs of worms its worth doing-Marriages does pellets with flubenvet (the only licensed poultry wormer in the UK and the only one to do all worms) already mixed in. Keep the hens space limited for 7 days and feed the pellets-mine are done 2 or three times a year.